Taking air samples during a mold inspection is important for several reasons. Mold spores are not visible to the naked eye, and the types of mold present can often be determined through laboratory analysis of the air samples. Having samples analyzed can also help provide evidence of the scope and severity of a mold problem, as well as aid in assessing human exposure to mold spores. After remediation, new samples are typically taken to help ensure that all mold has been successfully removed. Air samples can be used to gather data about mold spores present in the interior of a house. These samples are taken by using a pump that forces air through a collection device which catches mold spores. The sample is then sent off to a laboratory to be analyzed.
There are several types of devices used to collect air samples that can be analyzed for mold. Some common examples include:
- Impaction samplers that use a calibrated air pump to impact spores onto a prepared microscope slide;
- Cassette samplers, which may be of the disposable or one-time-use type, and also employ forced air to impact spores onto a collection media; and
- Airborne-particle collectors that trap spores directly on a culture dish. These may be utilized to identify the species of mold that has been found.
An air sample alone is not enough to confirm or refute the existence of a problem, and such testing needs to be accompanied by visual inspection and other methods of data collection, such as a surface sample. Indoor airborne spore levels can vary according to several factors, and this can lead to skewed results if care is not taken to set up the sampling correctly. Also, since only spores are collected with an air sample and may actually be damaged during collection, identification of the mold type can be more difficult than with a sample collected with tape or a cultured sample. Air samples are good for use as a background screen to ensure that there isn’t a large source of mold not yet found somewhere in a home. This is because they can detect long chains of spores that are still intact. These chains normally break apart quickly as they travel through the air, so a sample that reveals intact chains can indicate that there is mold nearby, possibly undiscovered during other tests and visual examination.